The worse thing you can do when in between jobs, is nothing. Not only will it show a gap in employment on your resume — a red flag — but the skills you possess will suffer as well.
While searching for that next executive level position, practice whatever your skill set is, don't let your knowledge become rusty. Stay up with the news and where business fads are going, they change a mile a minute.
If you have skill to freelance; do. If you like to volunteer; do.
Don't make the mistake others will of letting your business IQ drop just because you are not currently in the mix of things. You'll be back sooner or later, and it will be much sooner if you can show employers you are ready to hit the ground running.